US6456801B1 - Image forming apparatus with a sheet-size specifying function - Google Patents

Abstract

The present invention provides an image forming apparatus for reading an image on a document having a main scanning direction and a sub scanning direction and forming a copy image of the image on a copy image forming medium. When a sheet feeding section selects a manual feeding tray to feed the copy image forming mediums therefrom, an automatic document upsetting section two-dimensionally detects a size of a first one of the copy image forming mediums fed from the manual feeding tray. A controlling section controls a reading section to read the image in accordance with the detected size of the copy image forming mediums, and controlling the image forming section for forming the copy image on the copy image forming mediums.

Description

BACKGROUND OF THE INVENTION

Conventionally, a manual feeding unit has been employed in printing on non-standard sheet, OHP, thick paper, or the like with a copying machine. The manual feeding unit comprises a tray placing a sheet and a member for guiding edges arranging parallel to the sheet-feeding direction. The most of the manual feeding units has a structure for determining the size of the placed sheet in the main scanning direction by sliding the guiding member in the main scanning direction.

On the other hand, the size in the sheet-feeding direction (the sub scanning direction) is assumingly determined as the maximum size presumable from the sheet size in the main scanning direction. When the actual size of the sheet in the sheet-feeding direction is smaller than the assumed maximum size, the rear end edge of the sheet is detected by a sensor and the printing is forcedly stopped in detecting the rear end edge in accordance with the installed program. If the printing is stopped, however, the document scanning operation continues till the maximum size of the document is scanned completely. The carriage thus continues the unnecessary operation even after the printing is stopped.

In addition, the size in the sheet-feeding direction is an assumed size, and thus the scanner performs the scanning assuming the sheet has the presumable maximum size in the sheet-feeding direction. Therefore, when the actual size in the sheet-feeding direction is smaller than the assumed maximum size, the redundant data in an area in which the actual document is not exist is rejected. This process terribly decreases the scanning operation speed in printing with use of the manual feeding unit. In other words, the printing speed with use of the manual feeding unit cannot be increased due to this process.

Further, according to the conventional apparatus the printing has to be started in the condition where the size in the sheet-feeding direction is assumingly determined as the presumable maximum size. The sorts of functions that can be used in this condition are so limited in comparing with the printing using a sheet-feeding cassette. More specifically, in order to set the binding space, the area to be printed needs to be adjusted. The adjustment is useful in the case where the document size is given. When the printing is performed with use of the manual feeding unit, however, the precise sheet size in the sheet-feeding direction is not given. In such a condition, the area to be printed cannot be adjusted, and thus the adjusting operation will be determined as invalid.

Further, the conventional manual feeding unit detects the size of the sheet in the main scanning direction. The apparatus thus needs to be provided with a size detecting mechanism and a sensor, and the components increases, which complicates the structure of the apparatus, resulting in the increase of the manufacturing cost.

FIG. 1 shows the structure of the digital copying machine as the conventional image apparatus to describe in detail.

As shown in FIG. 1, the copying machine comprises as a basic structure a main controllingsection201, ascanner controlling section203, an automaticdocument feeding section205, a printerengine controlling section204, a sheetfeeding controlling section206, an automatic document upsettingsection controlling circuit209, and asheet feeding cassette207.

The copying machine further comprises amanual feeding tray208 having a sheetsize detection circuit217 for detecting the sheet size in the main scanning direction. An automaticdocument upsetting section216 does not detect the sheet size, and thus has no sensor. Similarly, a sheetguide controlling section210 also does not perform the sheet size detection, and thus controls a motor merely to align the stacked sheets.

As shown in the diagram, the conventional copying machine has a rear endedge detection circuit218 for detecting the sheet feeding direction in feeding the sheet. After detecting the rear end edge of the sheet by this section, the printerengine controlling section204 performs a processing of stopping the printing by force.

On the other hand, with the conventional copying machine, the user can manually set the sheet size in the manual feeding printing.

The operation of the digital copying machine as the conventional image forming apparatus will be described in detail with reference to the flow chart of FIG.2.

The user sets a document on a document mounting table (step S101), aligns sheets on the manual feeding tray208 (step S102), sets the size of the sheet manually fed by operating a control panel202 (step S103), and pushes a start button on the control panel202 (step S104).

After pushing the start button, the parameters are set in accordance with the sheet size (step S105), and then the first sheet is picked up from themanual feeding tray208 to be fed into the inside of the apparatus (step S106) to be subjected to the predetermined printing process (step S107), ejected thereafter (step S108).

When the manual feeding tray208 mounts more than one sheet, the sheets are serially picked up from themanual feeding tray208 to be subjected to the printing process (steps S109 to111).

If the sheet size is wrongly set in the above-mentioned process, the document size and the sheet size does not match each other, which prevents the proper printing. With the result, unclear printing may occur and the printing efficiency will be adversely affected.

BRIEF SUMMARY OF THE INVENTION

The present invention has been developed in consideration of the above, and is intended to automatically determining the sheet size in the sheet conveying direction prior to the printing operation such that various settings or processings can be attained prior to the printing. Further, the redundant scanning operation exceeding the sheet size does not need to be performed since the sheet size can be specified prior to the printing operation. As a result, the interval between the printing operations can be decreased, and thus the printing speed can be increased. In addition, according to the present invention, the sheet size is automatically preformed and user does not need to perform the complicated operation, and thus the printing efficiency is remarkably improved. Still further, according to the present invention, the manual feeding unit may have only a sheet holding function, and can be formed in a simple structure, resulting in the decrease of the manufacturing cost.

In order to attain the above-mentioned object, the present invention provides an image forming apparatus for reading an image on a document having a main scanning direction and a sub scanning direction and forming a copy image of the image on a copy image forming medium, comprising: a conveying section which automatically conveys the document; a reading section which reads the image on the document; an image forming section which forms an image on the copy image forming medium; a sheet feeding section having a plurality of sheet feeding cassettes respectively containing corresponding one of sizes of the copy image forming mediums, and a manual feeding tray for manually stacking a desired size of the copy image forming mediums, the sheet feeding section feeds sheets selectively from one of the manual feeding tray and the sheet feeding cassettes; an automatic document upsetting section which two-dimensionally detects a size of a first one of the copy image forming mediums fed from the manual feeding tray when the sheet feeding section selects the manual feeding tray to feed the copy image forming mediums therefrom; and a controlling section which controls the reading section to read the image in accordance with the detected size of the copy image forming mediums, and controls the image forming section for forming the copy image on the copy image forming mediums.

The present invention further provides an image forming apparatus for reading an image on a document having a main scanning direction and a sub scanning direction and forming a copy image of the image on a copy image forming medium, comprising: a document conveying section which automatically conveys the the document; a reading section which reads the image on the document; an image forming section which forms an image on the copy image forming medium; a sheet feeding section having a plurality of sheet feeding cassettes respectively containing corresponding one of sizes of the copy image forming mediums, and a manual feeding tray which manually stacks a desired size of the copy image forming mediums, the sheet feeding section feeds sheets selectively from one of the manual feeding tray and the sheet feeding cassettes; an automatic document upsetting section having a copy image forming medium aligning guide movable in two directions and an optical sensor for optically detecting one of a presence and an absence of the copy image forming medium, the automatic document upsetting section which two-dimensionally detects a size of a first one of the copy image forming mediums fed from the manual feeding tray in accordance with a moving distance of the copy image forming medium aligning guide and an output signal of the sensor; and a controlling section which controls the reading section to read the image in accordance with the detected size of the copy image forming mediums, and controls the image forming section for forming the copy image on the copy image forming mediums, and, when the image forming section forms the copy image on a plurality of the copy image forming mediums, the controlling section controls the image forming section to form a first image by feeding one of the copy image forming mediums from the automatic document upsetting section, and controls the image forming section to form a second image by feeding one of the copy image forming mediums from the manual feeding tray.

Still further, the present invention provides an image forming apparatus for reading an image on a document having a main scanning direction and a sub scanning direction and forming a copy image of the image on a copy image forming medium, comprising: a document conveying section which automatically conveys the document; a reading section which reads the image on the document; an image forming section which forms an image on the copy image forming medium; a sheet feeding section having a plurality of sheet feeding cassettes respectively containing corresponding one of sizes of the copy image forming mediums, and a manual feeding tray for manually stacking a desired size of the copy image forming mediums, the sheet feeding section feeds sheets selectively from one of the manual feeding tray and the sheet feeding cassettes; an automatic document upsetting section having a mechanical sensor for mechanically detecting one of a presence and an absence of the copy image forming medium, the automatic document upsetting section two-dimensionally detects a size of a first one of the copy image forming mediums fed from the manual feeding tray in accordance with an output signal of the sensor; and a controlling section which controls the reading section to read the image in accordance with the detected size of the copy image forming mediums, and controls the image forming section for forming the copy image on the copy image forming mediums, and, when the image forming section forms the copy image on a plurality of the copy image forming mediums, the controlling section controls the image forming section to form a first image by feeding one of the copy image forming mediums from the automatic document upsetting section, and controls the image forming section to form a second image by feeding one of the copy image forming mediums from the manual feeding tray.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a block diagram showing the structure of the conventional image forming apparatus.

FIG. 2 is a flow chart showing the flow of the manual feeding printing process of the conventional image forming apparatus.

FIG. 3 is a block diagram showing a structure of a digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing the inner structure of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention.

FIG. 5 is a sectional view showing the inner structure of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention.

FIG. 6 is a flow chart showing the flow of the manual feed printing process of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention.

FIG. 7 is an explanatory view showing the sheet size detection process in the automatic document upsetting section of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention.

FIG. 8A is a flow chart showing the flow of the main scanning direction sheet size detection process of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention.

FIG. 8B is a flow chart showing the flow of the main scanning direction sheet size detection process of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention.

FIG. 8C is a flow chart showing the flow of the main scanning direction sheet size detection process of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention.

FIG. 9 is a flow chart showing the flow of the main scanning direction sheet size detection process of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention.

FIG. 10 is a flow chart showing the flow of the sheet feeding direction sheet size detection process of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention.

FIG. 11 is an explanatory view showing the relationship between the scanning operation in manual feeding printing and the printing operation to compare the prior art and the present invention.

FIG. 12 is a block diagram showing a structure of a digital copying machine as an example of the image forming apparatus according to the second embodiment of the present invention.

FIG. 13 is a sectional view showing the inner structure of the digital copying machine as an example of the image forming apparatus according to the second embodiment of the present invention.

FIG. 14 is an explanatory view showing the sheet size detection process in the automatic document upsetting section of the digital copying machine as an example of the image forming apparatus according to the second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, the first embodiment of the present invention will be described.

FIG. 3 shows a digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention to describe in detail.

As shown in FIG. 3, the digital copying machine comprises amain controlling section1 for controlling the entire apparatus. Themain controlling section1 is connected to acontrol panel2, ascanner controlling section3, and a printerengine controlling section4 so as to communicate each other. Thescanner controlling section3 is connected to an automaticdocument feeding section5.

The printerengine controlling section4 is connected to a sheetfeeding controlling section6 and an automatic document upsettingsection controlling circuit9. The sheetfeeding controlling section6 is connected to asheet feeding cassette7 and amanual feeding tray8. The output terminal of the automatic document upsettingsection controlling circuit9 is connected to input terminals ofmotors11 and12. The output terminal of asensor15 is connected to the input of the automatic document upsettingsection controlling circuit9.

In this embodiment, an optical device such as a photoreflector is employed as thesensor15, but the other device can be used.

With the above structure, when the operator operates operating buttons (not shown) on thecontrol panel2 to set predetermined parameters, the set parameters are sent to themain controlling section1. Themain controlling section1 executes a predetermined control on the basis of the set parameters. Thecontrol panel2 displays various data of the copying machine.

Thescanner controlling section3 drives the automaticdocument feeding section5. The printerengine controlling section4 drives the sheetfeeding controlling section6. The sheetfeeding controlling section6 drives thesheet feeding cassette7 and amanual feeding tray8. The printerengine controlling section4 also drives the automatic document upsettingsection controlling circuit9. The automatic document upsettingsection controlling circuit9 drives a sheetguide controlling section10. The sheetguide controlling section10 controls themotors11 and12 to control the sheet feeding from sheet guides13a,13b, and14. The output from thesensor15 arranged near the central portion of an automaticdocument upsetting section16 is fed back to the automatic document upsettingsection controlling circuit9. The feed back information is used by the automatic document upsettingsection controlling circuit9 to control the sheetguide controlling section10 and determine the sheet size.

The inner structure of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention will be described next in detail in conjunction with FIGS. 4 and 5.

There is provided on the top of anapparatus body90 an automatic document feeding device (hereinafter referred to as “ADF”)97 so as to be opened/closed. TheADF97 also functions as a document cover. TheADF97 is provided to automatically feed sheet-like documents one by one. The apparatus is provided at the front portion on its top face with various operating keys for setting a copying condition and instructing the start of the copying operation. There are also provided at the front portion on its top face with a control panel having various indicators. On the right side of the apparatus, there are detachably provided asheet feeding cassette57 capable of containing a small amount of sheets and a largecapacity sheet cassette55.

Thesheet feeding cassette57 has amanual feeding tray56 for manually feeding a sheet. Theapparatus body90 has in a lower portion a plurality of detachablesheet feeding cassettes52,53, and54. Thesheet feeding cassettes52,53, and54 respectively contain sheets which have a predetermined size and laid in the lateral/longitudinal directions. Thesheet feeding cassettes52,53, and54 are selected in necessity.

On the left side of theapparatus90, there is provided afinisher80 for receiving the printed sheet. Theapparatus body90 has below the control panel at the front portion thereof an inserting opening (not shown) to which an optomagnetic disk as a storage medium for storing image data or the like. An optomagnetic disk device (not shown) is provided in theapparatus body90. On the rear side of theapparatus90, a parallel port (not shown), a serial port (not shown), and an SCSI (not shown), and the like are arranged.

The parallel port connects the apparatus and the outer apparatus such as a PC when the apparatus is employed as a printer. In maintaining the apparatus, the control information of the apparatus is read through the serial port. The serial port is also used to connect the apparatus and the outer apparatus such as a PC in setting the functions of the apparatus. The SCSI is provided to perform the communication of command/data between the apparatus and a printer controller (not shown) arranged outside the apparatus.

Theapparatus body90 also have therein ascanner section91 for attaining image data and aprinter section92, by which copying operation and facsimile operation can be attained. On the top face of theapparatus body90, a document mounting table93 for mounting a document D as an object to be read, anADF97 for automatically feeding the document onto the document mounting table93, which can be opened with respect to the document mounting table93.

TheADF97 has adocument tray88, anempty sensor89, apickup roller94, a feedingroller95, an aligningroller pair96, an aligning sensor (not shown), a size sensor (not shown), and a feedingbelt98.

The document D is set on thedocument tray88. Theempty sensor89 detects presence/absence of the document. Thepickup roller94 picks the documents from thedocument tray88 one by one. The feedingroller95 conveys the document picked up by thepickup roller94. The aligningroller pair96 align the front edge of the document. The aligning sensor is arranged in the upstream of the aligningroller pair96 to detect the arrival of the document. The size sensor detects the size of the document D. The feedingbelt98 is arranged to cover almost entire surface of the document mounting table93.

A plurality of documents are set in thedocument tray88 to lay their faces up, and are picked up one by one such that the bottom sheet, i.e., the last page of the documents is picked up at first among the documents. The picked documents are aligned by the aligningroller pair96, and then serially sent to a predetermined position on the document mounting table93.

On the end portion of theADF97 on the opposite side of the aligningroller pair96 with respect to the feedingbelt98, there are arranged an inverting roller20, anon-inverting sensor21, aflapper22, and asheet ejection roller23. The document D from which image data is read by ascanner section91 which will be described later is sent from the document mounting table93 by the feedingbelt98. The document D passes through the inverting roller20, theflapper22, and thesheet ejection roller23 to be ejected onto adocument ejection section24 on theADF97. When the rear side of the document D needs to be read, theflapper22 is switched so that the inverting roller20 inverts the document D sent by the feedingbelt98. The inverted document D is then sent to a predetermined position on the document mounting table93 once more by the feedingbelt98.

TheADF97 has a feeding motor for driving thepickup roller94, the feedingroller95, and the aligningroller pair96, and a conveying motor for driving the feedingbelt98, the inverting roller20, and thesheet ejection roller23.

Thescanner section91 arranged in theapparatus90 has alight source25 such as a fluorescent lamp for irradiating the document D mounted on the document mounting table93, afirst mirror26 for deflecting a reflection light reflected from the document D in a predetermined direction.

Thelight source25 and thefirst mirror26 are attached to afirst carriage27 arranged below the document mounting table93. There is arranged above the first carriage27 asize sensor28 for detecting the size of the document mounted on the document mounting table93. Thefirst carriage27 is provided so as to move parallel to the document mounting table93. Thefirst carriage27 is driven by the driving motor via a belt having gears so as to reciprocate below the document mounting table93.

There is arranged below the document mounting table93 asecond carriage29 capable of moving parallel to the document mounting table93. Thesecond carriage29 is provided with second andthird mirrors30 and31 for deflecting the reflection light reflected from the document D and deflected by thefirst mirror26 such that the second andthird mirrors30 and31 are arranged to be perpendicular to each other. Thesecond carriage29 is moved in accordance with the movement of thefirst carriage27 by the belt having gears for driving thefirst carriage27, or the like. Thesecond carriage29 is moved at a half speed of that of thefirst carriage27 by the belt having gears for driving thefirst carriage27 in parallel to thefirst carriage27 along the document mounting table93.

There are provided below the document mounting table93 animaging lens32 for focusing the reflection light from thethird mirror31 on thesecond carriage29, and a CCD sensor for photoelectrically converting the reflection light focused by theimaging lens32. Theimaging lens32 is arranged on a plane including an optical axis of the light deflected by thethird mirror31 so as to be moved by a driving mechanism. Theimaging lens32 images the reflection light at a desired magnification by moving itself. TheCCD34 photoelectrically converts the incident reflection light, and outputs an electric signal corresponding to the read document D.

On the other hand, theprinter section92 has alaser exposing device40. Thelaser exposing device40 has asemiconductor41 as a light source, apolygon mirror36 as a scanning member, apolygon motor37 as a scanning motor, and anoptical system42. The laser light emitted from thesemiconductor41 is deflected serially by thepolygon mirror36. In this time, thepolygon mirror36 is rotated by thepolygon motor37 at a predetermined rate described later. The laser light is deflected by thepolygon mirror36 and guided tophotosensitive drums44ato44d(described later) through theoptical system42. Thelaser exposing device40 having the structure as mentioned above is fixedly supported by a supporting frame (not shown) of anapparatus90.

Thesemiconductor41 is switched on/off in accordance with the image data of the document D read by thescanner section91. The laser light is led to thephotosensitive drums44ato44dvia thepolygon mirror36 and theoptical system42 to form electrostatic latent images on the circumferential surfaces of thephotosensitive drums44ato44dby scanning the circumferential surfaces of thephotosensitive drums44ato44d. Theimage printer section92 has the rotatablephotosensitive drums44ato44das image carriers in an approximately central portion of theapparatus90. On the circumferential surfaces of thephotosensitive drums44ato44d, the desired electrostatic latent images exposed by the laser light emitted from thelaser exposing device40 are formed.

The photosensitive drums44ato44dare surrounded by chargingchargers45,developers46, peeling chargers47,transfer chargers48, peeling crawls,cleaning devices50, and adischarger51. The chargingchargers45 charge the circumferential surfaces of thephotosensitive drums44ato44dat a predetermined potential. Thedevelopers46 supply toner as developer to the electrostatic latent images formed on the circumferential surfaces of thephotosensitive drums44ato44din order to develop the images with a desired concentration. The peeling chargers47 peel the materials fed from thesheet feeding cassettes52,53,54,55, and57, i.e., copy sheets P off thephotosensitive drums44ato44d. Thetransfer chargers48 transfer the toner images formed on thephotosensitive drums44ato44dto the sheets P. The peeling crawls peel the sheets P off the circumferential surfaces of thephotosensitive drums44ato44d. Thecleaning devices50 clean the toner left on the circumferential surfaces of thephotosensitive drums44ato44d. Thedischargers51 discharge the circumferential surfaces of thephotosensitive drums44ato44d.

Theapparatus body90 has in a lower portion the drawablesheet feeding cassettes52,53, and54 stacked on each other. Thesheet feeding cassettes52,53, and54 respectively contain sheets that have a predetermined size. On the side of thesheet feeding cassettes52,53, and54, the largecapacity sheet cassette55 is provided. There is detachably provided above the largecapacity sheet cassette55 thesheet feeding cassette57 also functions as themanual feeding tray56.

There is provided in theapparatus90 conveyingpaths58 extending from thesheet feeding cassettes52,53,54,55, and57 to thetransfer chargers48 through a transfer section. At the ends of the conveyingpaths58, a fixingdevice60 is arranged. On the side wall of the apparatus, which faces the fixingdevice60, anejection opening61 is formed to which afinisher80 is attached.

Each of thesheet feeding cassettes52,53,54,55, and57 is provided with apickup roller63 for picking sheets from the cassettes one by one. The conveyingpaths58 has a plurality of sheet feeding roller pairs64 for conveying the copy sheets P picked up by thepickup roller63 through the conveyingpaths58.

In the conveyingpaths58, there is provided a resistroller pair65 in the upstream of thephotosensitive drums44ato44d. The resistroller pair65 corrects the leaning of the picked sheet P, and aligns the toner images on thephotosensitive drums44ato44dand the copy sheet P at the front edge.

The resistroller pair65 feeds the copy sheet P at the same speed as the rotation speed of thephotosensitive drums44ato44d. In front of the resistroller pair65, i.e., on the side of the feeding roller pairs64, an aligningsensor66 for detecting the arrival of the copy sheet P is arranged. The copy sheets P picked up by one of thepickup rollers63 one by one is sent to the resistroller pair65 to be aligned, then sent to the transfer section by a conveyingbelt67.

In the transfer section, the developer images, i.e., the toner images formed on thephotosensitive drums44ato44dare transferred to the sheet P by thetransfer chargers48. The copy sheet P to which the toner images are transferred is peeled off the circumferential surfaces of thephotosensitive drums44ato44dby the peeling chargers47 and the peeling crawls (not shown), and sent to the fixingdevice60 by conveyingbelt67 constituting a part of the conveyingpath58. The developer images are melted to be fixed on the copy sheet P by the fixingdevice60. After fixing the images, the copy sheet P is sent to theeject tray81 of thefinisher80 through the ejection opening61 by a feedingroller pair68 and anejection roller pair69.

Theapparatus body90 is provided below the conveyingpath58 with an automatic sheet upsetting device (ADU)70 for upsetting the copy sheet P passing through the fixingdevice60 and sending it to the resistroller pair65 again. To be more specific, theADU70 has a temporary accumulatingsection71, an upsettingpath72, apickup roller73, and a feedingroller75. The temporary accumulatingsection71 temporarily accumulates the copy sheet P. The upsettingpath72 is a branch of the conveyingpath58 and up sets the copy sheet P passing through the fixingdevice60 and leads to the temporary accumulatingsection71. Thepickup roller73 picks the copy sheets P accumulated in the temporary accumulatingsection71 one by one. The feedingroller75 feeds the sheet picked up by thepickup roller73 to the resistroller pair65 through the conveyingpath74. The branching point of the conveyingpath58 and the upsettingpath72 is provided with a splittinggate76. The splittinggate76 selectively splits the copy sheets P to the ejection opening61 or the upsettingpath72.

In performing the double-side copying, the copy sheet P passing through the fixingdevice60 is led to the upsettingpath72 by the splittinggate76 to be upset, and temporarily accumulated in the temporary accumulatingsection71. The copy sheet P is sent to the resistroller pair65 through the conveyingpath74 by thepickup roller73 and the feedingroller pair75.

The copy sheet P is aligned by the resistroller pair65, and then sent to the transfer section again so that a toner image is transferred on the rear side of the copy sheet P. The copy sheet P then passes through the conveyingpath58, the fixingdevice60, and theejection roller pair69, and ejected to theeject tray81 of thefinisher80.

With use of theADU70, the copy sheet P can be ejected in a condition where the copied face is turned down. More specifically, in the similar manner to that of performing the double-side copying, the toner image is transferred and fixed to the surface of the copy sheet P, and the copy sheet P is temporarily accumulated in the temporary accumulatingsection71.

The copy sheet P is then sent to the resistroller pair65 through the conveyingpath74 by thepickup roller73 and the feedingroller pair75 so as to be aligned by the resistroller pair65. The copy sheet P thereafter passes through the conveyingpath58, the fixingdevice60, and theejection roller pair69, and ejected to theeject tray81 of thefinisher80.

The detailed description of the manual feeding printing process of the digital copying machine as an example of the image forming apparatus according to the first embodiment of the present invention in conjunction with the flow chart of FIG.6. In explaining the operation, FIGS. 3-5 should be also referred to in necessity.

The user sets a document on the document mounting table93 (step S1), aligns sheets on the manual feeding tray8 (step S2), and pushes a start button (not shown) on the control panel2 (step S3).

After pushing the not shown start button, the first sheet is picked up from themanual feeding tray8 to be fed into the inside of the apparatus90 (step S4). The fed sheet passes through the fixingdevice60 by the conveying belt, and then makes a U-turn in front of the ejection opening to be sent to the automaticdocument upsetting section16.

Themain controlling section1 two-dimensionally detects the sheet size of the sheet sent to the automaticdocument upsetting section16 with use of the sheet guides13a,13b, and14 provided in the automaticdocument upsetting section16 in accordance with the method the detail of which will be described later (step S5).

If the sheet size detected in the above-mentioned manner is larger than the size on which the printing can be performed by the apparatus, a predetermined error indication is presented, and the sheet is automatically ejected or the user is provoked attention (step S10).

If the detected sheet size is within the size on which the printing can be performed by the apparatus, the printing process is performed on the sheet stored in the automaticdocument upsetting section16 at first (steps S7, S8, S9, and S11), and then the sheets on themanual feeding tray8 are serially picked up from themanual feeding tray8 to be subjected to the printing process as in the conventional method (steps S12 to S14)

Next, the sheet size detection process in the automaticdocument upsetting section16 will be described in detail in conjunction with FIG. 7

As shown in FIG. 7, the sheet size of the sheet sent to the automaticdocument upsetting section16 in the main and sub scanning directions is detected with use of the three adjustable sheet guides13a,13b, and14 provided for aligning the sheets in the automaticdocument upsetting section16.

In this embodiment, the detection of the sheet size in the main scanning direction and that in the subscanning direction respectively need at least one of the sheet guides13a,13b, and14.

At first of the detecting process, the sheet guides13aand13bperpendicular to the main scanning direction are slid in order to detect the size in the main scanning direction. The sheet guides13aand13bare driven by more than onemotor12. The moving amount of the sheet guides13aand13bis calculated in the automatic document upsettingsection controlling circuit9 on the basis of the period of the rotating time of themotor12. In employing a stepping motor, the rotating time is calculated from the stepping number and the like.

At the initial state, the sheet guides13aand13bare set at the positions such that the width of the sheet in the main scanning direction is the maximum. In detecting that the sheets are stacked, the automatic document upsettingsection controlling circuit9 controls the sheetguide controlling section10 to drives themotors11 and12, thereby moves the sheet guides13aand13b. The automaticdocument upsetting section16 has thesensor15 in the region in which the sheets are stacked. Thesensor15 detects the presence of the sheets only in the condition where the sheets are stacked horizontally. The automaticdocument upsetting section16 may have a plurality of thesensor15.

The flow of the main scanning direction sheet size detection process will be described below with reference to the drawings of FIG.8 and the flow chart of FIG.9.

The sheet guides13aand13bare moved at the beginning of the process to decrease the distance therebetween. The sheets held by the sheet guides are bowed to ascend at the central portion (see FIG.8A). In this time, thesensor15 cannot detect the presence of the sheets. When thesensor15 cannot detect the presence of the sheets, the automatic document upsettingsection controlling circuit9 stops the movement of the sheet guides13aand13b.

Subsequently, the sheet guides13aand13bare moved in the direction in which the sheet width increases, till thesensor15 can detect the presence of the sheets again (see FIG.8B). When thesensor15 detects the presence of the sheets, the automatic document upsettingsection controlling circuit9 stops the movement of the sheet guides13aand13b(see FIG.8C). The distance between the sheet guides at this time is determined as the main scanning width of the sheet (steps S21 to S26).

The feeding direction sheet size detection process of will be performed in the similar manner.

The flow of the feeding direction (the subscanning direction) sheet size detection process will be described next with reference to the flow chart of in FIG.10.

Thesheet guide14 is set in advance at the positions such that the size of the sheet is set at the maximum, and moved to decrease the sheet size. When the sheets are bowed to ascend at the central portion and thesensor15 cannot detect the presence of the sheets, the automatic document upsettingsection controlling circuit9 stops the movement of the sheet guide.

Subsequently, thesheet guide14 is moved in the opposite direction. When thesensor15 detects the presence of the sheets again, the movement of thesheet guide14 is stopped. The position of the sheet guide at this time determines the sheet size in the subscanning direction (steps S31 to S36).

It goes without saying that the feeding direction sheet size detection process may be performed prior to the main scanning direction sheet size detection process.

Next, the relationship between the scanning operation in manual feeding printing and the printing operation according to the first embodiment will be described below in conjunction with FIG. 11 to compare the prior art and the present invention.

As shown in the upper half of FIG. 11, according to the prior art, the start button is pushed at first, and then various parameters are set in the apparatus. The scanning operation is then started to attain image data. When the scanning operation is started, the printerengine controlling section4 controls the sheetfeeding controlling section6 to feed the sheets from themanual feeding tray8, and starts the printing operation. If the sheet size is A4 in this time, the printerengine controlling section4 stops the printing operation when the rear end edge of the sheets is detected. The scanner, however, continues the scanning operation till the scanning of the A3 region as the maximum size which can be printed has finished. The scanned data obtained after the printing operation is stopped is rejected. Accordingly, the redundant scanning operation increases the period from the time at which the first printing has finished to the time at which the second printing is started, and decreases the printing speed.

In contrast, with use of the method according to the present invention as shown in the lower half of FIG. 11, the sheet is picked up from the manual feeding tray to be fed to the automaticdocument upsetting section16, which is performed simultaneously with the setting of various parameters after pushing the start button. After the automaticdocument upsetting section16 detects and determines the sheet size, the scanning operation is started. Simultaneously with the start of the scanning operation, the sheet is fed from the automaticdocument upsetting section16 to perform the first printing. In this printing, the sheet size has already been determined, the scanning operation is performed only in the same area as that of the sheet. Accordingly, no redundant scanning operation is performed and thus the second printing operation can be performed without any waiting time. With this process, the printing speed is increased according to the first embodiment of the present invention.

The apparatus according to the prior art described before has a rear endedge detection circuit218 for detecting the sheet size in the sheet feeding direction during the sheet feeding operation. After detecting the rear end edge of the sheet by this section, the printerengine controlling section204 performs a processing of stopping the printing by force.

If the image forming apparatus according to the first embodiment of the present invention is provided with the rear endedge detection circuit218 and the sheetsize detection circuit217 for detecting the sheet size in the main scanning direction in themanual feeding tray208, the conventional method mentioned above can be also employed.

Similarly, even in the apparatus having the automaticdocument upsetting section16, if themain controlling section1 is constituted such that the software processing can be switched by the user's setting of various parameters on thecontrol panel2, the conventional method can be also applied. In this case, the sheet size on the manual feeding tray can be also set by operating thecontrol panel2, and the manual feeding printing operation can be performed to meet more suitably the user's request.

The following is the description of the second embodiment of the present invention.

FIG. 12 shows the structure of a digital copying machine as an example of the image forming apparatus according to the second embodiment of the present invention, wherein the automatic document upsetting section is formed in a stackless type. The difference to the first embodiment will be mainly described below.

As shown in FIG. 12, the second embodiment employs the stackless type of automatic document upsetting section, therefore, the sheet cannot be stored in the automatic document upsetting section. The sheet size detection process according to this embodiment is thus performed in the following manner.

The sheet picked up from themanual feeding tray8 is sent to the automaticdocument upsetting section16, but merely passes through the automaticdocument upsetting section16, without being stacked. In this time, the sheet passing time is detected by thesheet detecting sensor15 in the automaticdocument upsetting section16, simultaneously with the detection of the sheet. On the basis of the detected sheet passing time and the feeding speed, the sheet size in the feeding direction is calculated.

FIG. 13 shows the inner structure of the digital copyingmachine101 as an example of the image forming apparatus according to the second embodiment of the present invention.

As shown in FIG. 13, there is provided on the top of anapparatus body102 of the digital copying machine101 a scanner section104 and aprinter section106.

On the top face of theapparatus body102, a document mounting table108. On the document mounting table108, a document D as an object to be read is mounted. There is also provided on the top face of theapparatus body102 anADF109 for automatically feeding the document onto the document mounting table108. The document D laid on adocument tray109aof theADF109 is conveyed by a conveying guide (not shown), and ejected to anejection tray109cby aplaten roller109b. By conveying the document in this manner, the document D is exposed by an exposing lamp110 of the scanner section104 described later to read the image on the document D during the period in which the document D is conveyed by theplaten roller109b.

There are stacked on thedocument tray109aof theADF109 the document D such that the face to be read is laid upward. When a plurality of documents are stacked on thedocument tray109aof theADF109, the documents are fed one by one from the top of the stacked documents.

The scanner section104 arranged in theapparatus body102 has the exposing lamp110 and afirst mirror112. The exposing lamp110 is a light source such as a halogen lamp for irradiating the document D conveyed by theADF109 or the document D mounted on the document mounting table108. Thefirst mirror112 deflect a reflection light reflected from the document D in a predetermined direction. The exposing lamp110 and afirst mirror112 are attached to a first carriage114 arranged below the document mounting table108.

The first carriage114 is provided so as to move parallel to the document mounting table108. The first carriage114 is driven by a scanner motor (the driving motor)116 via a belt having gears (not shown) so as to reciprocate below the document mounting table108. The scanner motor116 comprises a stepping motor or the like. There is arranged below the document mounting table108 asecond carriage118 capable of moving parallel to the document mounting table108. Thesecond carriage118 is provided with second andthird mirrors120 and122 such that the second andthird mirrors120 and122 are arranged to be perpendicular to each other.

The second andthird mirrors120 and122 are provided to deflect the reflection light reflected from the document D and deflected by thefirst mirror112.

Thesecond carriage118 is transmitted with a rotation force of the scanner motor116 via the geared belt or the like for driving the first carriage114 and moved thereby in accordance with the movement of the first carriage114. Thesecond carriage118 is moved at a half speed of that of the first carriage114 in parallel to the first carriage114 along the document mounting table108.

There are provided below the document mounting table108 animaging lens124 and aCCD sensor126. Theimaging lens124 is arranged on a plane including an optical axis of the light deflected by thethird mirror122 so as to be moved by a driving mechanism. Theimaging lens124 images the reflection light from thethird mirror120 on thesecond carriage118 at a desired magnification (in the main scanning direction) by moving itself.

TheCCD126 photoelectrically converts the incident reflection light focused by theimaging lens124 in accordance with the image processing clock signal sent from a main CPU described later, and outputs an electric signal corresponding to the read document D.

The magnification in the subscanning direction can be changed by changing the document conveying speed by theADF109 or the moving speed of the first carriage114.

In reading the document D conveyed by theADF109, the irradiating position of the exposing lamp110 is fixed to the position shown in FIG.13. In contrast, when the document D mounted on the document mounting table108 is read, the irradiating position of the exposing lamp110 is moved from left to right along the document mounting table108.

On the other hand, theprinter section106 has alaser exposing device128. When the circumferential surface of thephotosensitive drum130 is scanned with the laser light from thelaser exposing device128, an electrostatic latent image is formed on the circumferential surfaces of thephotosensitive drum130.

Theprinter section106 has thephotosensitive drum130. Thephotosensitive drum130 is arranged rotatably on the right side of the approximately central portion of theapparatus102 and functions as an image carrier.

The circumferential surface of thephotosensitive drum130 having the above-mentioned structure is exposed by the laser light emitted from thelaser exposing device128 are formed to obtain the desired electrostatic latent image. Thephotosensitive drum130 are surrounded by a chargingcharger132, adeveloper134, atransfer charger138, peelingcrawl140, acleaning device142, and adischarger144.

The chargingcharger132 charges the circumferential surface of thephotosensitive drum130 at a predetermined potential. Thedeveloper134 supplies toner as developer to the electrostatic latent image formed on the circumferential surface of thephotosensitive drum130 in order to develop the image with a desired concentration.

Thetransfer charger138 integrally has a peelingcharger136 for peeling the material fed from thesheet feeding cassettes148 and150 described later, i.e., copy sheet P off thephotosensitive drum130. Thetransfer charger138 transfers the toner image formed on thephotosensitive drum130 to the sheet P. The peeling crawls140 peels the sheet P off the circumferential surface of thephotosensitive drum130. Thecleaning device142 cleans the toner left on the circumferential surface of thephotosensitive drum130. Thedischargers144 discharges the circumferential surface of thephotosensitive drum130.

Theapparatus body102 has in a lower portion the upper andlower cassettes148 and150 drawable from the apparatus and stacked on each other. Thecassettes148 and150 respectively contain sheets that have a predetermined size. On the side of theupper cassette148, amanual feeding tray154 is arranged.

There is provided in theapparatus102 conveyingpaths156 extending from thecassettes148 and150 to thephotosensitive drum130 and thetransfer chargers138 through a transfer section. At the ends of the conveyingpaths156, a fixingdevice158 having a fixinglamp158ais arranged. There is provided above the fixingdevice158 anejection opening160.

Each of the upper andlower cassettes148 and150 is provided with a sheet feeding roller162 and a separation roller163 for picking sheets P from the cassettes one by one. The conveyingpaths156 has sheet feeding roller pairs164. There are provided a plurality of sheet feeding roller pairs164 for conveying the copy sheets P picked up by the sheet feeding roller162 and the separation roller163 through the conveyingpaths156.

In the conveyingpaths156, there is provided a resistroller pair166 in the upstream of thephotosensitive drum130. The resistroller pair166 corrects the leaning of the picked sheet P, and aligns the toner image on thephotosensitive drum130 and the copy sheet P at the front edge. The resistroller pair166 feeds the copy sheet P at the same speed as the rotation speed of thephotosensitive drum130. In front of the resistroller pair166, i.e., on the side of the feeding roller pairs164, an aligningsensor168 for detecting the arrival of the copy sheet P is arranged.

The copy sheet P picked up from thecassettes148 and150 by the sheet feeding roller162 one by one is sent to the resistroller pair166 to be aligned, then sent to the transfer section. In the transfer section, the developer image, i.e., the toner image formed on thephotosensitive drum130 is transferred to the sheet P by thetransfer charger138.

The copy sheet P to which the toner images are transferred is peeled off the circumferential surface of thephotosensitive drum130 by the peelingcharger136 and the peelingcrawl140, and sent to thefixing device158 by a conveying belt (not shown) constituting a part of the conveyingpath156. The developer images are melted to be fixed on the copy sheet P by the fixingdevice158. After fixing the images, the copy sheet P is sent to the eject tray172 in theapparatus body102 through the ejection opening160 by anejection roller pair170.

Theapparatus body102 is provided on the right side of the conveyingpath156 with an automaticsheet upsetting device174 for upsetting the copy sheet P passing through the fixingdevice158 and sending it to the conveyingpath156 again. There are also provided at the front portion on the top face of theapparatus body102 with a control panel by which various copying conditions such as a copying magnification are set or instructs the starting of the copying operation.

FIG. 14 shows the sheet conveying path of the digital copying machine using the automaticdocument upsetting section18 having no stack, as an example of the image forming apparatus according to the second embodiment of the present invention. The sheet size is obtained when the sheet passes through the automaticdocument upsetting section18. For example, when an actuator is employed as thesheet detecting sensor15, the actuator lever of thesheet detecting sensor15 is downed to detect the sheet size, and the printerengine controlling section4 calculates the sheet size L in the conveying direction on the basis of the period T of time during which the lever is downed and the conveying speed V, as shown below.

conveying direction sheet size L=sheet detecting time T/conveying speed V

On the other hand, the sheet size in the main scanning direction is detected in accordance with the conventional manner with use of a sheetsize detecting circuit17 using the guide arranged on themanual feeding tray8.

In the second embodiment as described above, the sheet size in the conveying direction can be detected simultaneously with the conveying of the sheet without stacking the sheet in the automaticdocument upsetting section16, and thus the period of time from the push of the start button to the start of the printing operation can be decreased in comparing with the apparatus using the automaticdocument upsetting section16 having a stack.

Although embodiments of the present invention have been described in detail, the following advantages are attained according to the present invention:

According to the present invention, the sheet size in the sheet conveying direction can be determined in advance, and the sheet size is given in performing the printing operation. Since the sheet size is determined prior to the printing operation, and thus various settings or processings can be attained prior to the printing.

The other advantage of the present invention is that the redundant scanning operation exceeding the sheet size does not need to be performed since the sheet size can be specified prior to the printing (scanning) operation. As a result, the interval between the printing operations can be decreased, and thus the printing speed can be increased.

Further, according to the present invention, the user does not need to manually determine the size of the sheet laid on the manual feeding unit, and thus the operation is remarkably simplified.

Still further, according to the present invention, the sheet aligning guide of the ADU is employed to detect the sheet size, thereby the ADU is given the sheet size detection function. Accordingly, the sheet size detection needs not to be performed in the manual feeding unit. With this constitution, the manual feeding unit may have only a sheet holding function, and can be formed in a simple structure, resulting in the decrease of the manufacturing cost.

In addition to the above, the apparatus having no automatic document upsetting section can be used in the similar manner by employing the present invention and the conventional method. Further, if the sheet size in the main scanning direction and that in the subscanning direction are detected separately, i.e., the former is detected is detected by the conventional method and the latter is detected by the method according to the present invention, the time from the pushing of the start button to the start of the actual printing operation can be decreased. Also in the case where the apparatus using the automatic document upsetting section having no stack, the conventional method and the present invention can be employed in conjunction.

Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Claims (9)

What is claimed is:

1. An image forming apparatus for reading an image on a document having a main scanning direction and a sub scanning direction and forming a copy image of the image on a copy image forming medium, comprising:

conveying means for automatically conveying the document;

reading means for reading the image on the document;

image forming means for forming an image on a copy image forming medium;

sheet feeding means having a plurality of sheet feeding cassettes respectively containing corresponding one of sizes of the copy image forming medium, and a manual feeding tray for manually stacking a desired size of the copy image forming medium, the sheet feeding means feeding sheets selectively from one of the manual feeding tray and the sheet feeding cassettes;

automatic document upsetting means for two-dimensionally detecting a size of a first one of the copy image forming medium fed from the manual feeding tray when the sheet feeding means selects the manual feeding tray to feed the copy image forming medium therefrom; and

controlling means for controlling the reading means to read the image in accordance with the detected size of the copy image forming medium, and controlling the image forming means for forming the copy image on the copy image forming medium.

2. The image forming apparatus according toclaim 1, wherein the automatic document upsetting means has a copy image forming medium aligning guide movable in two directions and a copy image forming medium detecting section, and two-dimensionally detects a size of a first one of the copy image forming medium fed from the manual feeding tray in accordance with a moving distance of the copy image forming medium aligning guide and an output signal of the copy image forming medium detecting section.

3. The image forming apparatus according toclaim 2, wherein the copy image forming medium detecting section is an optical sensor arranged on a part of a plane of the automatic document upsetting means in order to optically detect one of a presence and an absence of the copy image forming medium.

4. The image forming apparatus according toclaim 1, wherein, when the image forming means forms the copy image on a plurality of copy image forming mediums, the controlling means controls the image forming means to form a first image by feeding one of the copy image forming mediums from the automatic document upsetting means, and controls the image forming means to form a second image by feeding one of the copy image forming mediums from the manual feeding tray.

5. The image forming apparatus according toclaim 1, further comprising operation inputting means for inputting instruction from outside of the apparatus, the operation inputting means for inputting the size of copy image forming mediums in advance.

6. The image forming apparatus according toclaim 1, further comprising indicating means for indicating a predetermined alarm when the copy image forming medium size two-dimensionally detected by the automatic document upsetting means exceeds an area within which image forming operation can be performed by the image forming means.

7. The image forming apparatus according toclaim 1, wherein the automatic document upsetting means further comprises a mechanical sensor constituted to drive in accordance with movement of the copy image forming medium.

8. An image forming apparatus for reading an image on a document having a main scanning direction and a sub scanning direction and forming a copy image of the image on a copy image forming medium, comprising:

a document conveying section which automatically conveys the document;

a reading section which reads the image on the document;

an image forming section which forms an image on a copy image forming medium;

a sheet feeding section having a plurality of sheet feeding cassettes respectively containing corresponding one of sizes of copy image forming mediums, and a manual feeding tray for manually stacking a desired size of the copy image forming mediums, the sheet feeding section feeds sheets selectively from one of the manual feeding tray and the sheet feeding cassettes;

an automatic document upsetting section having a copy image forming medium aligning guide movable in two directions and an optical sensor which optically detects one of a presence and an absence of the copy image forming medium, the automatic document upsetting section two-dimensionally detects a size of a first one of the copy image forming mediums fed from the manual feeding tray in accordance with a moving distance of the copy image forming medium aligning guide and an output signal of the sensor; and

a controlling section which controls the reading section to read the image in accordance with the detected size of the copy image forming mediums, and controlling the image forming section which forms the copy image on the copy image forming mediums, and, when the image forming section forms the copy image on a plurality of the copy image forming mediums, the controlling section controls the image forming section to form a first image by feeding one of the copy image forming mediums from the automatic document upsetting section, and controls the image forming section to form a second image by feeding one of the copy image forming mediums from the manual feeding tray.

9. An image forming apparatus for reading an image on a document having a main scanning direction and a sub scanning direction and forming a copy image of the image on a copy image forming medium, comprising:

a document conveying section which automatically conveys the document;

a reading section which reads the image on the document;

an image forming section which forms an image on a copy image forming medium;

a sheet feeding section having a plurality of sheet feeding cassettes respectively containing corresponding one of sizes of copy image forming mediums, and a manual feeding tray for manually stacking a desired size of the copy image forming mediums, the sheet feeding section feeds sheets selectively from one of the manual feeding tray and the sheet feeding cassettes;

an automatic document upsetting section having a mechanical sensor for mechanically detecting one of a presence and an absence of the copy image forming medium, the automatic document upsetting section two-dimensionally detecting a size of a first one of the copy image forming mediums fed from the manual feeding tray in accordance with an output signal of the sensor; and

a controlling section which controls the reading section to read the image in accordance with the detected size of the copy image forming mediums, and controls the image forming section for forming the copy image on the copy image forming mediums, and, when the image forming section forms the copy image on a plurality of the copy image forming mediums, the controlling section controls the image forming section to form a first image by feeding one of the copy image forming mediums from the automatic document upsetting section, and controls the image forming section to form a second image by feeding one of the copy image forming mediums from the manual feeding tray.

Images